This long clip shows the entire process of welding a large piece of metal before the advent of the industrial electric welder. Notice the forge and the foreman overseeing the work. Check out the muscles on those guys. Many of them are probably recent immigrants. It seem incredible that the average weekly wage for such hard labor was $3 to $5. The shot was made at the Westinghouse plant where electric generators were made.
The photographer was the famous Billy Bitzer who later teamed up with director D.W. Griffith and who photographed many classic movies such as "Birth Of A Nation","Intolerance", "The Battle of Elderbush Gulch" and "Hearts Of The World"
"A group of men weld one area of a large ring in a fire. They lift the ring, which is hanging horizontally on chains, out of the fire. Four men hammer the hot area on the ring into shape while the remaining men hold the ring. They put the ring into the fire again, take it out, and take it over to a machine which continuously hammers down on that area of the ring. The men then take it away from the machine and hammer it themselves into shape. The ring is presumably a piece of a generator." - Library Of Congress
Library of Congress, Motion Picture, Broadcasting, and Recorded Sound Division.
I worked in a body shop years ago and learned some of the same techniques. We heated steal till it was red hot then sprinkled in ground metal and pounded it into place and it worked every bit as well as modern welding except it was extremely time consuming and very labor intensive.
We did this whenever the welder was down mainly on frames, but every now and then on sheet metal as well.